The present invention relates to a dust cover mounting structure of a hydraulic shock absorber.
Conventionally, there has been a hydraulic shock absorber, as described in Japanese Patent Application Laid-Open Publication (JP-A) No. 57-129942, such that a damper tube and a piston rod are provided, a spring seat is provided in the piston rod, a suspension spring is supported to the spring seat via a spring rubber, and a mounting portion of a dust cover is held between the spring seat and the spring rubber.
However, the prior art has the following problems.
(1) The spring seat is provided with a standing-up rib on an annular outer edge, and the mounting portion of the dust cover is rotatably received along an inner periphery of the annular rib. Accordingly, a torsion force generated at a time of extension and compression of the suspension spring rotates the dust cover to which the torsion force is applied via the spring rubber while rubbing the dust cover against the spring seat, whereby dusts are generated on the basis of abrasion of the dust cover so as to pollute an environment. This dust generation is significant when the dust cover is made of a resin.
(2) Since the mounting portion between the spring rubber and the dust cover is simply laminated on the spring seat, it is quite possible that the spring rubber and the dust cover are dropped off in a step of attaching an assembly obtained by laminating the spring rubber and the dust cover on the spring seat to the piston rod so as to bring into contact and align with the spring seat, so that an assembling property is deteriorated.
(3) An outer periphery of the spring rubber is restricted neither by the spring seat nor the dust cover. Accordingly, when the spring rubber repeatedly receives a compression force on the basis of a spring force of the suspension spring, the spring rubber freely protrudes in a direction of the outer periphery so as to be yielded and deformed, so that there is a risk that the spring rubber is broken or dropped off.
An object of the present invention is to prevent dusts from being generated due to rotation of a dust cover at a time of holding a mounting portion of the dust cover between a spring rubber and a spring seat which receive a suspension spring.
Further, another object of the present invention is to improve an assembling property of a spring seat, a dust cover and a spring rubber and to prevent the spring rubber from being yielded and deformed.
In accordance with the present invention, there is provided a dust cover mounting structure of a hydraulic shock absorber comprising:
a damper tube;
a piston rod;
a spring seat provided in the piston rod;
a suspension spring supported to the spring seat via a spring rubber; and
a mounting portion of a dust cover held between the spring seat and the spring rubber,
wherein the spring seat is formed in a non-annular outer shape, a standing-up rib is provided in an outer edge thereof, and the mounting portion of the dust cover is formed in a non-annular outer shape profiling an inner periphery of the rib of the spring seat and is received in the inner periphery of the rib.